Abstract We report on the electron transports in a novel quantum point contact (QPC) structure, in which the heterointerface is corrugated with 16 nm periodicity and 1.8 nm height. The conductance in this QPC has distinct step structures, which are equal to 2 e 2/ h multiplied by 0.3, 0.7, 1.3, 1.8, 2.5, and 3.1. Moreover, the first step (0.3(2 e 2/ h)) was accompanied by a quasi-plateau. Several features such as the temperature dependence of this QPC resemble those of conventional QPC. The anomalous conductance quantization may be related to interacton effects enhanced by periodic potential modulation in one-dimensional system.